"Zafarullah Khan Jamali has decided to join the PTI," the spokesman told Geo.

The two leaders have agreed to meet soon to make a formal announcement.

Meanwhile, PTI Additional Secretary Information Faisal Javed Khan also made the announcement of former prime minister's joining on Twitter.

“Welcome to Ex PM of Pakistan and Sr. Politician Mir Zafarullah Khan Jamali to Pakistan Tehreek-e-Insaf. He had left PML-N over principles despite being in Power. Jamali sab is a good addition to our team,” he tweeted.

He had served as the 13th Prime Minister of Pakistan from 2002 until his resignation in 2004 under Pervez Musharraf’s military rule.